This invention relates to an ore pass inspection system that allows imaging of the ore pass in an underground mine. This ore pass inspection system is especially useful in cases of hang-ups or blockages within the ore pass. This inspection system can also be used to help clear such hang-ups or blockages.
An ore pass is a generally vertical or near-vertical passage excavated between at least two levels in an underground mine. The levels occur at different vertical displacements in the mine. The vertical distances between such levels, and thus the vertical extent of the ore pass, may range up to hundreds of feet or even more. Such ore passes provide a passageway for delivering mine products (i.e., ore, coal, and the like) from a higher level to a lower level within the mine. Generally, the lower level contains ore carts, carriages, trams, or other transport devices which allow the mine products to be removed directly or indirectly out of the mine. In some cases, the lower level can serve several higher levels through the same or different ore passes.
The interior walls of an ore pass may contain surface structures ranging from smooth to very rough. The surface features may depend, for example, on the geological structures traversed by the ore pass, the nature of the mining tool or apparatus used in boring out the ore pass, and similar factors. Additionally, the cross-sectional dimensions of such ore passes may vary. Likewise, the sizes, shapes, and structures of the mining products being transported via the ore pass may vary greatly. Thus, from time to time in a given ore pass, the mining products may xe2x80x9chang upxe2x80x9d within the ore pass. The just mentioned factors contribute to the likelihood of such hang-ups and blockages within ore passes. The likelihood of such blockages will be significantly higher in some cases (e.g., rough ore pass surfaces, xe2x80x9cbottlenecksxe2x80x9d within the ore pass, non-vertical passageways within the ore pass, large and irregularly shaped mine products). Once a hang-up or blockage occurs, the piling up of additional mine product on top of the hang-up often packs the blockage more tightly and makes removal of the blockage more difficult.
Clearing an ore pass hang-up or blockage presents significant safety concerns. For example, a miner at the lower end of the ore pass attempting to remove the blockage could be exposed to any material dislodged from the hang-up. If the miner is standing at the bottom end of the ore pass, and directing a disrupting force upwards into the ore pass toward the hang-up, any sudden rush of ore attending a successful clearing operation may trap the miner and cause serious injury or death. As of the time of this invention, there have been at least five ore pass-related fatalities in the preceding five years in the United States, and a far larger number of ore pass hang-up-related injuries.
The United States has about 100 to 200 mines containing working ore passes. Any given mine may have one or more ore passes; some mines have upwards of 10 or even more ore passes. Depending on the factors identified above, the frequency and likelihood of an ore pass hang-up may vary considerably. In some case, an ore pass may become hung-up only rarely in other cases, it may be an almost daily occurrence. Likewise, and for similar reasons, the degree of difficulty in clearing such a hang-up varies widely. Numerous techniques to remove the blockage have been developed. These include, for example, delivering blows to structures adjoining or related to the ore pass; placing a small blasting charge either just inside the ore pass or as close to the blockage as possible using, for example, a long pole; or propelling the explosive charge as a ballistic slug toward the location of the hang-up. Alternatively, a separate long hole may be drilled from below (mobilizing a drill rig in the passageway beneath the blockage) in order to deliver a blasting agent through the drilled hole into the hang-up. Clearly, the latter tactic is both time consuming and expensive. In some cases, the mine operator may choose to abandon the blocked ore pass and bore a new one.
U.S. Pat. No. 4,930,595 discloses a method of remotely determining the profile of a subterranean passage within a mine using an instrument pod that can be moved along the passage. The pod includes a rangefinder for determining the distances from a defined longitudinal axis of the pod to multiple points on the internal wall of the passage and providing an output signal representing the profile of the passage. A clinometer is used to indicate the orientation of the pod in the passage. The signals are transmitted to a remote location and provide a visual representation of the profile of the passage at a given location. As the pod is moved, successive representations at different locations are obtained. The pod is preferably also provided with a television camera and lighting so that the wall of the passage can also be visually inspected. Since the pod moves by gravity, it is generally intended for use by being lowered down the passage; in some cases, the pod can be pulled up the passage.
U.S. Pat. No. 4,023,862 provides a coal mining method wherein the coal seam is disintegrated by utilizing a jet of hot oil under pressure. Since an operation can be remotely controlled in a deep mine shaft, exposure of mine workers can be minimized. The method further reduces the amount of coal dust produced and, thus, reduces the risk of dust explosions. A TV camera can be mounted on the mining machine for transmitting a picture of the operation to the surface so that appropriate guiding signals can be transmitted to the machine.
U.S. Pat. No. 4,708,395 discloses a method and apparatus for hydraulically mining a coal seam using a monitor and a hydraulic jet powered by high pressure water. The monitor includes means for remotely positioning the jet vertically and horizontally so that the jet can be aimed at any location within the zone of a mine face being mined. This system is especially useful in hazardous locations within a mine (e.g., unstable areas where the risk of roof falls is significant).
U.S. Pat. No. 5,069,108 discloses a blasting device for unblocking ore passes, backfill raises, mine draw points, or other near vertical raises where rocks or other materials normally fall freely but may get blocked during use. The device includes a propulsion unit including an air chamber mounted at the end of a hollow tube with an inlet for receiving pressurized air and at least one outlet for allowing compressed air jets to exit downwardly from the air chamber to propel the propulsion unit upwardly. A reservoir is mounted on the propulsion unit and adapted to hold an explosive charge and an igniter which can be remotely activated.
As those skilled in the art realize, it is generally more effective to attack a blockage from below. But efforts from below place the workers at maximum risk since once the blockage is clear, the hung-up materials will, of course, continue their fall through the ore pass. Even if the blockage is not completely cleared, material dislodged from the blockage place workers located below at significant risk.
Thus, there still remains a need for an apparatus and method that integrally permits placing the apparatus in a location immediately under a hang-up in an ore pass in order to clear the hang-up while minimizing the risks to the operator. There additionally remains a need for an apparatus and method that substantially eliminates guesswork in placing a device to clear an ore pass hang-up, and that employs an image based guiding mechanism to direct the apparatus to a preferred position for clearing a hang-up. There further remains needs for method for clearing blockages and for an apparatus and that is reusable. The present invention addresses these unresolved needs.
The present invention discloses an apparatus for clearing a material hang-up in an essentially vertical shaft having walls which is used for moving material from a higher level to a lower level, said apparatus comprising:
(1) a platform having an upper surface and a lower surface and at least two ends, wherein the platform is movable along a longitudinal direction within the shaft;
(2) a remotely controllable propulsion unit affixed to the lower surface of the platform capable of propelling the platform along the longitudinal direction within the shaft and up to the hang-up;
(3) an imaging unit affixed to the upper surface of the platform capable of generating an image of an upward view within the shaft, wherein the image is transmittable to a remote viewer, and wherein the image can be viewed by an operator to assist in controlling and operating the apparatus;
(4) one or more extensible immobilizing units affixed to the ends of the platform, wherein the immobilizing units are remotely controllable, and wherein the immobilizing units, when activated by the operator, immobilize the platform within the shaft;
(5) a remotely controllable clearing unit affixed to the platform and adapted for clearing the hang-up within the shaft; and
(6) a remote controller for controlling the propulsion unit, the immobilizing units, and the clearing unit;
wherein the apparatus can be controlled and operated by the operator using the remote controller at a safe distance from the shaft. This apparatus is especially adapted for use in ore passes in underground mines. Preferably, the immobilizing unit allows the operator to immobilize the apparatus at a fixed longitudinal position within the ore pass by providing members that can contact the walls of the ore pass in a manner to immobilize the platform in the desired position (i.e., generally a position from which the hang-up can be cleared). Preferably the apparatus has a light source to provide light for the imaging unit; preferably, both the light source and the imaging unit can be remotely controlled. If desired, the imaging unit may incorporate a zoom-type lens.
In a significant embodiment of the apparatus, the propulsion unit comprises a gas receiving chamber, a source of a gas under high pressure in communication with the chamber, and at least one gas nozzle affixed to the chamber and projecting downward therefrom. Preferably, the gas source is located at a remote, and protected, position relative to the platform (e.g., at a safe location near the bottom of the ore pass). In a further significant embodiment, the imaging unit includes a light source directing light generally upward along the ore pass above the platform and an imaging device capable of generating the image. When the apparatus is positioned just below the ore pass hang-up, the image allows the operator to view the blockage and place the platform in position to remove or breakup the blockage.
In an important embodiment of the apparatus, the extensible immobilizing unit includes at least one balloon or bladder inflatable by gas under pressure, and a first remotely controllable valve capable of controllably admitting the pressurized gas into the balloon(s) or bladder(s). Furthermore, in an alternative important embodiment, the extensible immobilizing unit includes at least one prong or leg extendably engaged to a remotely controllable driving unit capable of controllably extending the prong. In operation, the balloon(s) and/or prong(s) are activated so as to extend out from the platform and contact the walls of the ore pass. The activated balloon(s) and/or prong(s) effectively lock the platform in place by applying pressure through the balloon(s) and/or prong(s) or leg(s). In another important embodiment of the apparatus, the extensible immobilizing unit or units can also be remotely retractable to allow the apparatus to be removed entirely or repositioned as desired. For example, the extensible immobilizing unit or units include one or more balloons, the retractable mobilizing unit or units would include a second remotely controllable valve for controllably releasing gas from the one or more balloons. Where the extensible immobilizing unit includes one or more prongs or legs, the retractable mobilizing unit would allow retraction of the prongs or legs. Of course, the extensible immobilizing unit can be modified to allow both activation (i.e., extension) and deactivation (i.e., retraction).
In an advantageous embodiment of the apparatus, the unit for clearing ore pass hang-ups includes a device to deliver high-impact blows to the blockage in general or to a particular location in the hang-up (e.g., to xe2x80x9ckeyxe2x80x9d pieces of material in the hang-up that appear to be responsible for the hang-up). In an alternative advantageous embodiment, the unit for clearing the ore pass hang-up includes a stream of a fluid under high pressure to breakup the hang-up.
Where these methods of breaking up the hang-up fail, the platform can be equipped with a remotely controlled explosive material or charge. In such cases, the apparatus preferably allows the explosive charge to be affixed or attached to blockage so that the apparatus itself can be removed from the ore pass before the charge is remotely activated. Of course, if desired, explosive charges could be used without first attempting to use other methods. Thus, in another significant embodiment of this invention, the unit for clearing the ore pass hang-up includes an emplacement unit and an explosive charge, wherein the emplacement unit includes: (1) a remotely controllable drive unit; and (2) a holder having a proximal end and a distal end, wherein the proximal end is pivotally and swivelably affixed to the drive unit; wherein the distal end is releasably holding the explosive charge; wherein the drive unit is capable of causing the holder to be moved in order to move the explosive charge to the desired location; and wherein the explosive charge further includes (a) a detonation device and (b) an attachment element whereby the explosive charge can be attached to the desired location on the hang-up. Preferably the detonation device allows the explosive charge to be triggered remotely. Suitable attachment elements include, for example, adhesives, grappling hooks or devices, and the like. Additionally, the explosive charge can be of the plastic type which can simply be xe2x80x9cpackedxe2x80x9d within voids or crevices within the hang-up. Preferably, the platform is removed before the explosive charge is triggered. In some especially difficult hang-ups, a second platform (but without the imaging equipment) can be locked into place just below the explosive charge and the hang-up so as to direct the force of the charge up into the hang-up.
The invention furthermore provides a method for imaging and clearing a shaft or ore pass containing a hang-up using the above-discussed systems and apparatuses. More specifically, this method comprises:
(1) introducing an apparatus for clearing the hang-up into the lower end of the shaft blocked by the hang-up, wherein the apparatus is capable of:
(a) being remotely propelled within the shaft so that the apparatus can be positioned adjacent to and below the hang-up by an operator located at a safe distance from the lower end of the shaft;
(b) providing an image of an upward view of the shaft as the apparatus is propelled within the shaft and is positioned adjacent to and below the hang-up, where the image is transmitted to the operator,
(c) being remotely immobilized in a position adjacent to and below the hang-up by the operator, and
(d) remotely clearing the hang-up after being immobilized in a position adjacent to and below the hang-up;
(2) remotely propelling the apparatus upward within the shaft until the apparatus is positioned adjacent to and below the hang-up, wherein the image is used by the operator to guide the apparatus within the shaft;
(3) remotely immobilizing the apparatus adjacent to and below the hang-up; and
(4) remotely clearing the hang-up.